Gangliosides are a class of molecules which are glycolipids. Different gangliosides have been identified as prominent cell surface constituents of various transformed cells, including melanoma, as well as other tumors of neuroectodermal origin. See, e.g., Ritter and Livingston, et al., Sem. Canc. Biol. 2: 401-409 (1991). Oettgen, VCH Verlags Gesellschaft (Weinheim Germany 1989), incorporated by reference in their entirety.
Gangliosides are known as mono-, di-, tri or polysialogangliosides, depending upon the degree of glycosylation with sialic acid residues. Abbreviations employed to identify these molecules include "GM1", "GD3", "GT1", etc., with the "G" standing for ganglioside, "M", "D" or "T", etc. referring to the number of sialic acid residues, and the number or number plus letter (e.g., "GT1a"), referring to the binding pattern observed for the molecule. See Lehninger, Biochemistry, pg. 294-296 (Worth Publishers, 1981); Wiegandt, in Glycolipids: New Comprehensive Biochemistry (Neuberger et al., ed., Elsevier, 1985), pp. 199-260.
The monosialoganglioside GM2 has the structure: ##STR1## while GM1 has structure ##STR2## As noted, supra, the gangliosides are prevalent cell surface markers on transformed cells, such as melanoma. This has made them attractive targets for cancer research. Livingston, et al., Proc. Natl. Acad. Sci. USA 84: 2911-2915 (1987) incorporated by reference supra, describe results of a vaccine based trial, wherein subjects afflicted with melanoma received, as vaccines, either whole cells which present high levels of GM2, pure GM2 or pure GM2 plus bacterial adjuvant. Attention is also drawn to Livingston, et al., J. Clin. Oncol. 12(5): 1036-1044 (1994), and Irie, et al., U.S. Pat. No. 4,557,931, both of which are incorporated by reference, and deal with the use of GM2 as a vaccine.
There has also been interest in the manufacture and use of antibodies, such as monoclonal antibodies, which bind to gangliosides. Such antibodies share the common characteristics of all antibodies, including antigenic specificity, and are of interest both diagnostically and therapeutically. See, e.g., Kjeldsen, et al., U.S. Pat. No. 5,229,289; Nudelmann, et al., U.S. Pat. No. 5,240,833; Hakomori, et al., U.S. Pat. No. 5,308,614, and Hakomori, et al., U.S. Pat. No. 5,389,530. All of these patents are incorporated by reference, and all deal in large part with the generation of ganglioside specific antibodies.
There are difficulties unique to the immunology of gangliosides, which are touched upon briefly here. First, while these molecules are prevalent on transformed cells, they are also common on certain normal cells, such as neural cells. There is a risk, in administering gangliosides to a subject, that the resulting antibody response will damage normal cells. Indeed, certain autoimmune pathologies, such as Guillain-Barre' Syndrome, are characterized by autoimmune antibodies reactive with GM1 or GQ1b. See, e.g., Yuki, et al., J. Exp. Med. 178: 1771-1775 (1993); Aspinall, et al., Infect & Immun. 62(5): 2122-2125 (1994).
There is an additional practical problem in that gangliosides are extremely difficult to secure in amounts sufficient for immunization protocols. No practical synthetic method is presently available. As a result, gangliosides are secured via purification from tissue, such as bovine cranial tissues. Even under optimum conditions, the yields of pure gangliosides are vanishingly small. Further, purification from mammalian tissue carries with it the risk of transmitting contaminants such as viruses, prion particles, and so forth. Alternate methodologies for securing ganglioside specific antibodies are thus highly desirable.
Lipopolysaccharide, or "LPS" molecules are found on the surface of Gram negative bacteria. Many of these molecules are quite toxic, leading to toxic shock syndrome, endotoxemia, and other conditions. There is a great deal of diversity in the LPS molecules of different bacteria. Indeed, even within the confines of a particular type of bacteria, the LPS molecule may differ, between various serotypes/serovars.
The LPS molecules of Campylobacter jejuni ("C. jejuni") have been studied in some detail. Representative, but by no means exhaustive, of the studies on these LPS molecules, are Aspinall, et al., Eur. J. Biochem. 213: 1017-1027 (1993); Aspinall, et al., Biochem. 33: 241-249 (1994); Yuki, et al., Infect. & Immun. 62(5): 2101-2103 (1994); Aspinall, et al., Infect. & Immun. 62(5): 2122-2125 (1994). All of these references are incorporated by reference. The Aspinall 1993 paper is of particular interest in that it presents LPS structures for C. jejuni serovars 0:1, 0:4, 0:23, and 0:36. Aspinall et al., state that OS:1, OS:23 and OS:36 are mutally indistinguishable, and have chain termini identical to those of GM2, while the OS:4 chain terminus is identical to GD1a. Some of these papers discuss certain similarities between portions of the 0:19 LPS molecule and GM1, an idea also discussed by Wirguin, et al., Ann. Neurol. 35(6): 698-703 (1994), incorporated by reference, as well as by Aspinall, et al., Infect. & Immun. 52(5): 2122-2125 (1994); Yuki, et al., Infect. & Immun. 62(5): 2102-2103 (1994); Yuki, et al., J. Exp. Med. 178: 1771-1775 (1993).
C. jejuni bacteria are themselves implicated in gastrointestinal disorders, and there has been some interest and activity in developing diagnostic tests for determining the presence of C. jejuni in samples. See PCT Application WO86/01808 to Wright et al., U.S. Pat. No. 5,200,344 to Blaser, et al., U.S. Pat. No. 5,169,757, to Yamazaki, et al., and Japanese Patent Application 63-273497 on this point. One notes that in all of these references, the manner in which the antibodies are generated involves the use of whole cells. Blaser, et al., speak of an antigen unique to C. jenuni, but it is a protein, not a glycolipid.
There has been no linking of C. jejuni LPS antigens are a source for producing antibodies against GM2. Further, there has been no suggestion that the antibodies produced in this way may be used in diagnostic and therapeutic approaches to pathological conditions, such as cancer.
These are all features of the invention described herein, in detail, in the disclosure which follows.